Police are investigating the possibility that an Oxford student is being stalked after a series of incidents at a house in the Cowley area.A house of five female students from University College has experienced two instances of highly alarming and potentially illegal behaviour over the past few weeks, with the same man appearing twice at their house and behaving in a highly threatening manner.His attempts to break-in seem particularly focused on one of the women in the house, leading police to believe that he is a potential stalker.The first such instance came on Wednesday 9th October, when, as the student returned from a night out, the man managed to gain access to the house by unknown means.After spending some time in the house he was discovered by the woman when she woke, and found him attempting to kiss her as she lay in bed. He had entered her room and been using her laptop for some time as she slept unawares, also accessing her Facebook account and looking through her profile.Police have been attempting to track him using the fingerprints and DNA left in the house. A man was mistakenly taken into custody but later released.The same intruder returned last Thursday, and banged on the door in the early hours of the morning. One of the students opened the door to him after being unable to see who it was through the security lens in the door. She screamed upon recognising the man, waking the house, at which point he fled. She reported having also potentially heard somebody knocking on the window earlier in the evening.Both incidents followed a visit to the same nightclub earlier in the evening, lending credibility to a pattern of stalking. Police are using CCTV footage of the man walking up and down Cowley Road, taken from a number of shops and businesses, but so far have been unable to identify the individual.